2:51 p.m.
Author: timfox
Date: 2009-12-02 15:51:57 -0500 (Wed, 02 Dec 2009)
New Revision: 8508
Added:
trunk/src/main/org/hornetq/utils/MemorySize.java
Log:
added missing class
Added: trunk/src/main/org/hornetq/utils/MemorySize.java
===================================================================
--- trunk/src/main/org/hornetq/utils/MemorySize.java (rev 0)
+++ trunk/src/main/org/hornetq/utils/MemorySize.java 2009-12-02 20:51:57 UTC (rev 8508)
@@ -0,0 +1,143 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ * Red Hat licenses this file to you under the Apache License, version
+ * 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package org.hornetq.utils;
+
+import java.lang.ref.WeakReference;
+
+import org.hornetq.core.logging.Logger;
+
+/**
+ * A MemorySize
+ *
+ * @author Clebert Suconic
+ * @author Tim Fox
+ *
+ *
+ */
+public class MemorySize
+{
+ private static final Logger log = Logger.getLogger(MemorySize.class);
+
+ private static final int numberOfObjects = 10000;
+
+ private static Object newObject(final ObjectFactory factory) throws Exception
+ {
+ return factory.createObject();
+ }
+
+ public static boolean is64bitArch()
+ {
+ boolean is64bit = true; //Default to 64 e.g. if can't retrieve property
+
+ try
+ {
+ String arch = System.getProperty("os.arch");
+
+ if (arch != null)
+ {
+ is64bit = arch.contains("64");
+ }
+ }
+ catch (Exception e)
+ {
+ //Ignore
+ }
+
+ return is64bit;
+ }
+
+ public interface ObjectFactory
+ {
+ Object createObject();
+ }
+
+ public static int calculateSize(final ObjectFactory factory) throws Exception
+ {
+ final Runtime runtime = Runtime.getRuntime();
+
+ getMemorySize(runtime);
+
+ newObject(factory);
+
+ int i = 0;
+ long heap1 = 0;
+ long heap2 = 0;
+ long totalMemory1 = 0;
+ long totalMemory2 = 0;
+
+ //First we do a dry run with twice as many then throw away the results
+
+ Object[] obj = new Object[numberOfObjects * 2];
+
+ for (i = 0; i < numberOfObjects * 2; i++)
+ {
+ obj[i] = newObject(factory);
+ }
+
+ obj = new Object[numberOfObjects * 2];
+
+ heap1 = getMemorySize(runtime);
+
+ totalMemory1 = runtime.totalMemory();
+
+ for (i = 0; i < numberOfObjects; i++)
+ {
+ obj[i] = newObject(factory);
+ }
+
+ heap2 = getMemorySize(runtime);
+
+ totalMemory2 = runtime.totalMemory();
+
+ final int size = Math.round(((float)(heap2 - heap1)) / numberOfObjects);
+
+ if (totalMemory1 != totalMemory2)
+ {
+ //throw new IllegalStateException("Warning: JVM allocated more data what
would make results invalid " +
+ // totalMemory1 + ":" + totalMemory2);
+
+ log.warn("Warning: JVM allocated more data what would make results invalid
" +
+ totalMemory1 + ":" +
totalMemory2);
+ }
+
+ return size;
+ }
+
+ private static long getMemorySize(final Runtime runtime)
+ {
+ for (int i = 0; i < 5; i++)
+ {
+ forceGC();
+ }
+ return runtime.totalMemory() - runtime.freeMemory();
+ }
+
+ private static void forceGC()
+ {
+ WeakReference<Object> dumbReference = new WeakReference<Object>(new
Object());
+ // A loop that will wait GC, using the minimal time as possible
+ while (dumbReference.get() != null)
+ {
+ System.gc();
+ try
+ {
+ Thread.sleep(500);
+ }
+ catch (InterruptedException e)
+ {
+ }
+ }
+ }
+
+}